In the recent days, use of electrical devices has dramatically increased across multiple fields like transportation, businesses, education and so on. Proper function of electrical devices calls for reliable source of power for the electrical devices. Generally, the electrical devices that use electrical energy as the source of power include an energy storage system. Power packs such as battery packs are commonly used as energy storage systems in many electrical systems. A battery pack includes a plurality of batteries which are used to store energy in a chemical form.
In devices such as electric vehicles, batteries are used to power the motor system of the vehicle. Batteries in such devices store electrical and/or mechanical energy in the form of chemical energy and thereafter, supply the stored chemical energy in the form of electrical energy to the motor system. The chemical reactions in batteries are dependent on temperature. The chemical reactions may be exothermic, where heat is generated, or may be endothermic, where heat is absorbed during the process of the chemical reaction. In exothermic reactions, the batteries are subjected to overheating because the chemical reaction reinforces the heat generated by the current flow.
Generally, for a battery to have a high performance and longer life, the battery should be operated within an optimum temperature range. If the battery is in operation for a substantially long duration, the heat generated within the battery will cause the temperature within the battery to rise beyond the optimum temperature threshold thereby decreasing the performance and life of the battery. More often than not, the temperature range for operating a battery as specified by the battery manufacturer is much narrower than the temperature range for operating the battery as desired by the manufacturer of a device, for example the manufacturer of a vehicle, in which the battery is indented to be used. Further, the temperature variation from module to module in a battery pack leads to a different charge or discharge behavior of each module resulting in a decreased efficiency of the battery pack.
Furthermore, if an electric vehicle, is to be operated in extreme cold condition, the battery used therein should be heated to initiate the charging process Therefore, the battery assembly should be constructed such that by heating the battery pack, the temperature of the battery pack should rise within a minimal time period and further, the temperature deviation within the battery pack should be minimum.
In view of the above, there is a need for a power pack system which is capable of heating the energy storage system when the device, in which the power pack is used, is operated in extreme cold condition. Further, there is a need for a power pack system which is capable of dissipating heat generated by the chemical reaction within a battery cell.